Nerve stimulation is a commonly used method for localizing nerves before the injection of a local anesthetic, i.e., in regional anesthesia. More particularly, electrical nerve stimulation is used to obtain a defined response (e.g., evoked motor response (EMR), muscle twitch or patient sensation) to accurately locate a peripheral nerve or nerve plexus with a needle. The needle is thereafter used to inject anesthetic in close proximity to the nerve to block nerve conduction and provide a sensory and/or motor block for surgery and/or, eventually, analgesia for pain management. Such procedures require sterile conditions. To accomplish sterile conditions, clinicians typically use a disposable, fenestrated or non-fenestrated sheet/drape. The sterile drapes in current use, however, are not ideally adjusted to a particular medical need in the field of regional anesthesia and nerve blocks.
The electrical aspects of nerve stimulation as applied to regional anesthesia can give rise to particular challenges. For example, during performance of peripheral nerve block procedures, many clinicians utilize a peripheral nerve stimulator. A nerve stimulator is a valuable tool during application of nerve blocks to identify the nerve(s) and decrease the risk of nerve injury by an advancing needle. However, existing surgical drapes do not allow for a secure, sterile and convenient application of nerve stimulation during such procedures. Further, prior to a procedure, clinicians must locate a peripheral nerve stimulator, and bring/position the stimulator to the patient's bed-side in order to use it during the procedure. When such nerve stimulator is misplaced, the clinicians often need to perform the procedure without reliance on nerve stimulation, therefore compromising on patient safety. Additionally, such stimulators require maintenance, battery change, calibration and test for accuracy and electrical safety by biomedical electric technicians or engineers. Taken together, this makes the use of currently available, stand-alone, reusable nerve stimulators cumbersome and time-inefficient.
Further, the use of electrical nerve stimulators requires that one lead of the nerve stimulator be connected to the patient and the other to the stimulating needle. The nerve stimulator leads (cables) can easily become detached or disconnected during the procedure and result in an open electrical circuit and consequently, failure to electro-localize or detect a hazardous needle-nerve relationship. In addition, the nerve stimulator leads (cables) are typically of a multiple-use type and not sterile. Therefore, the presence of non-sterile electrical leads on the field can contaminate the sterile field during the procedure. In addition, the return electrode (+) is connected to the lead from the nerve stimulator and patients skin via an adhesive, such as an electroconductive gel. Most typically, electrocardiogram (EKG/ECG) electrodes are used for this purpose. However, it is common occurrence that this electrode gets disconnected during procedures due to dryness of the patient's skin or greasy/slick skin conditions after application of moisturizing lotion, etc. Similar problems with the risk of disconnect occur when gel on an EKG leads becomes dry/desiccated causing a faulty connection and/or poor adhesion to the skin. Although many nerve stimulators incorporate some means of detecting the electrical disconnect and resulting open circuit, this may not be easily detected in a busy, noisy, clinical environment, yet, the electrical failure may lead to wrong or hazardous placement of the needle too close or into the nerves and a consequent nerve injury. Further still, application of a ground electrode is another step in the procedure process and therefore increases the likelihood of error.
Thus, it would be advantageous to provide nerve block procedure drapes that overcome these shortcomings.